Protection of Extra High Voltage Transmission Line Using Oh Mega Distance Relay

8/9/2019 Protection of Extra High Voltage Transmission Line Using Oh Mega Distance Relay

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The Indian power system have grown at a phenomenal rate in

the last ten years, the increase in the networks and the requirementof the power transmission has introduced a number of newproblems in relation to protection.

The numerical relays has various features such as reverse zoneprotection, carrier protection, over current protection, highest overcurrent protection, permissive under reach and permissive overreach and self monitoring when compared withelectromagnetic,static relays and has facility of independentsetting of resistance and reactance reaches.

For analyzing the behavior of fault occurrence through cable,the setting and graduations for a feeders in the system can becalculated by incorporating all features latest ohmega distanceprotection available in the market.


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Introduction:y When a failure occurs on

any part of the system itmust be quickly detectedand disconnected fromthe system. It can bedetected by using relay.Fault may occur due towhich conductor is cutdown by the branch ofthe tree.

y The fault is detected bythe relay. The fault canbe cleared within fractionof second by usingnumerical relay.


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Protective Relay:

The protectiverelay is a device

that detects thefault and initiatesthe operation ofthe circuitbreaker to isolatethe defectiveelement from therest of system.


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Basic requirements of protectiveRelaying:

There are two groups of protective relaying:

1.Primary relaying

2.Back-up relaying

Primary relaying is the first line defense, whereasback up relaying functions only when primaryrelay fails.


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Characteristics of protective Relay:

1. Reliability

2. Selectivity

3. Speed

4. Sensitivity

5. Simplicity

6. Economy


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Relay classification:

1. Elecromechanical relays

2. Static relays

3. Numerical relays


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Electromechanical Relay:

Electromechanicalrelays are based on the

comparison betweenoperating torque/forceand restrainingtorque/force. Relayoperates when itsatisfies the condition :

Operating force >Restraining force


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tat c

Relay:

Static relay are suitable forcomplex functions such asgenerator protection, EHV-line protection etc. and arepreferred for almost allprotective systems. Staticrelay contains electronic

circuitry which mayinclude transistors, ICs,diodes and other electroniccomponents.


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Numerical Relay:

Numerical relay is

also known as

Microprocessor-

based protectiverelay. They are thelatest developmentin this area. With the

developments inVLSI technology,sophisticated andmicroprocessors are

coming up.


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Numerical Relay family:

1.Generator protection system.

2.Distance protection system.3.Transformer protection system.

4.Ohmega distance protection system.


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Ohmega Relay:The ohmega range of numeric

distance combines the power and

flexibility of microprocessor

technology. All faults loops and allzones are continuously monitored.

Ohmega 300 series relays are

suitable for distribution and sub-

transmission networks or any

application where a trip time of

35ms.

Ohmega 400 series relays aresuitable for transmission networks, or

any application that requires a trip

time of 20ms.


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CONCLUSIONy Finally, we implement the distance protection using

ohmega relay for the protection of EHV transmission

line.

y The relay setting for ohmega distance scheme and thezonal impedence and there time settings are noted

and are well supervised and faults will be calculated.


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Protection of Extra High Voltage Transmission Line Using Oh Mega Distance Relay